Essential MERN Stack Interview Questions and Answers in 2023
MERN stack is considered as one of the most powerful and demanding web technology stack in today’s market. Using MERN we can develop interactive and dynamic web applications and websites. It is a free open source JavaScript software stack.
Top MERN Stack Interview Questions and Answers
To stand strong in the world of competition and grab the opportunity you need to first prepare for the interview. So here we are to make your journey smoothe and which will help you to get the success you want, with some helpful MERN stack interview questions.
Lets look into the MERN stack developer interview questions and answers to enhance your skill set and knowledge.
MERN Stack Interview Questions for Freshers
1. What is meant by replication in MongoDB?
It is the process of synchronizing data across many servers. Because of replication data availability increases. With different copies of data on multiple database servers, replication protects the database from the loss of a single server. It allows you to recover from service interruptions & hardware failure.
2. How does React work?
Virtual DOM is created by react. First it runs a “diffing” algorithm, whenever there is a state change in a component. Second one is reconciliation, here it updates the DOM with the result of diff.
3. What is Mongoose?
Mongoose is also called an object document mapper. It is used to provide a schema based solution for the purpose of modeling application data. Validation, Typecasting, query construction, business logic hooks, and other, these are also functionalities of Mongoose.
4. What do you know about Asynchronous API?
Asynchronous API or non-blocking, all fall under the library of Node.js. Node.js servers never have to wait for API to return data. After accessing the API the server moves to the next one. The notification process of Node.js assists the server in receiving responses from previous API calls.
5. What is CallBack Hell?
A CallBack Hell is a condition, It occurs when many asynchronous functions are chained together. The asynchronous function expects call back, as it is a return parameter.
6. Explain higher order components(HOC)?
A HOC is basically a function that takes a component & returns a new component. It is a pattern that is obtained from React’s compositional nature. They are also called pure components.
Because they can accept any of the provided child components but they won’t change any behavior from their input components.
7. How does node prevent blocking code?
It does so, by providing a CallBack function. It gets called whenever a corresponding event is triggered.
8. What is a ReactDOM?
By using ReactDOM render method it renders a react element into the DOM. It is the top level React API.
9. What is Key?
It is a special string attribute which needs to be included while creating lists of elements. React gets help to identify which items changed, added or removed from the key.
10. How can we make node modules available externally?
We can do so by using module.export
MERN Stack Interview Questions for Experienced
11. Which are the 2 arguments that async.queue accepts as input in Node.js?
Task function & Concurrency value.
12. Explain stub in Node.js
Stubs are used for writing tests, which is an important step in development. It replaces the entire function which is getting tested.
13. Explain concept of a thread pool
The libuv library handles thread pool. Libuv is a C library which is multi-platform in nature & it provides support to asynchronous I/O-based operations for eg. networking, concurrency & file systems.
14. What do you know about smart components and dumb components?
Smart components are connected to the Redux store in the Redux context, or they manage their state.
Dumb components dont have state of thier own instead they are fully controlled by props received from their parent.
15. List the abbreviation of MERN
MERN in abbreviated form is:
16. What are the features of NodeJS?
Few features of NodeJS are:
- No buffering
- Library used is JavaScript
- Very fast in code execution
- Single thread ascendible
17. Explain occasion circle in NodeJS
Occasion circle is used for the purpose of processing and handling outer occasions & to change over them into a callback. This is the way that I/O calls, Node.js can alter starting with one demand and then onto the next one.
18. State the term I/O
I/O (Input/Output) refers to the program’s interaction with systems networks & disks. Some of the eg. are reading or writing data from or to a disk making HTTP requests and communicating to databases.
It is stacked to the machine memory for the purpose of running the program after the application begins.
19. State control stream work
Basically it is the non-specific code which keeps running in the middle of some non-concurrent work calls.
20. What do you know about Dependency Injection?
Dependency injection is utilized for separating the client creation dependencies from behavior, which lets you design a slackly coupled program. It also allows the modification of the behavior of applications by using the components.
Basically it allows injecting the service in ways that are not dependent on client consumption. So as a result the client can be prevented from changing dependencies underlying service modifications.
Cyber Success – Best MERN Stack Course in Pune
Cyber success is constantly working to shape and make skilled software engineers in today’s world of competition. If you are aspiring to work in the IT industry and keep growing in the field then cyber success is the best choice for you as our organization relies on hard work, truth and passion. Because of highly experienced trainers we are the most recognized IT center in India.
MERN stack development course at cyber success is thoughtfully designed & implemented by experts within the industry to meet the current needs and upcoming trends. The course focuses on efficiently teaching students on how to create applications using MERN stack.
Why you should choose us:
- At the end you will have a great understanding of HTML, CSS, & MERN.
- Also you will be great in front end technologies such as MongoDB, Angular, Nodejs, Express.js.
- Better understanding of testing of the MERN stack training module.
- Learn to use ReactJS to build a single page application.
- Grab hold of sessions that focus practical knowledge.
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